Railway signaling



H. A. WALLACE.

RAILWAY SIGNALING- APPLlCATlON FILED MAY 8. l9l8.

. 5 ,131. PatehtedNov. 16,1920.

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H. A. WALLACE. RAILWAY SlG PlALlNG. APPLICATION FILED M'AY 8(1918.

Patented Nov. 16,1920

INVENTOR WQ-WWW- UNITED STATES PATENT OFFICE.

HERBERT A. wALLAcn, or rrr'rsiannerr, PENNSYLVANIA, AssIGNoR To THE-UNION SWITCH & SIGNAL COMPANY, or swIssvALE, PENNSYLV RAILWAY SIGNALING.

1 359 131 Specification of Letters Patent.

Application filed May 8,

T 0 all 20 7mm 2'25 may concern:

Be it known that I, HERBERT A. WVALLACE, a citizen of the United States,residing at Pittsburgh, in the county of Allegheny and State ofPennsylvania, have invented certain new and useful Improvements inRailway Signaling, of which the following is a specification.

My invention relates to railway signaling, and particularly to signalingsystems of the type in which two relays are connected with the trackrails adjacent the ends of a stretch of track and are energized bycurrent supplied to the rails at an intermediate polnt 1n the stretch.

I willdescribe certain forms of apparatus embodying my invention andwill then point out the novel features thereof in claims.

In the accompanying drawings, Figure l is a diagrammatic view showingone form of railway signaling system embodying my invention. Figs. 2 and3 arediagrammatic views showing modifications of the means shown in Fig.l for controlling the polarlty of the current supplied to the trackrails, and also embodying my invention. F 1g. 4 is a fragmcntal viewshowing a modification of part of the apparatus shown in F 1g. 2. Figs.5, 6 and 7 are views showing means for supplying signaling current tothe track rails which may be substituted for the means shown in Figs. 1,2 and 3.

Similar reference characters refer to srmllar parts in each of the vieweferring first to Fig; l, the reference character E designates the trackrails of a stretch of railway track AB between two passing sidings C andD. The rails of the stretch AB are electrically isolated from the railsof the ac joining sections by insulated ioints 24. Located adjacenttheends of the stretch AB are two track relays R and R each ofwhich, ashere shown, comprises a track winding 2 and a line winding The trackwinding 2 of each relay is connected with the track rails, and the linewinding 3 is constantly supplied with alternating signaling current bymeans of a ransformer T or T To simplify the drawing, the sources ofcurrent are not illustrated. but it is understood that the primarywindings of transformers T and T as well as the primary winding oftransformer T Y Patented Nov. 16, 1920.

1918. Serial No. 233,209.

which supplies current to the track rails as hereinafter explained, areall connected with the same source of alternating current.

Alternating signaling current for the stretch by any suitable means. Asshown in F 1g. 1, this is accomplished by a single transformer T thesecondary of which is connected with the railsand the primary of whichis supplied with alternating signaling current of one instantaneouspolarity or the other by means hereinafter explained. This means forsupplying the signaling current rails may be replaced by other suitablemeans, such for example as by any one of the arrangements shown in Figs. 5, (3 and 7, wherein the rails are divided at or near the middle ofthe stretch A-B by insulated joints 24*, and signaling current issupplied to each of the track sections'so f InFig. 5, current issupplied to the two sections in multiple from the secondary oftransformer T suitable voltage reducing means such as resistances beinginterposed in the connections to the track rails as shown. In Fig. 6,the transformer T is provided with two secondary windings, one for eachtrack section; In Fig. 7, two transformers T are provided, one for eachtrack section.

Each track relay R and R comprises two contacts 4 and 5, which contactsoccupy intermediate or vertical positions when the relay is deenergized,that is, when current is out off from either or both of the relaywindings, and which contacts are swung to the left or to the rightaccording as the instantaneous polarity of the current in the trackwinding 2 is normal or reverse with respect to the polarity in winding3. Each relay is, consequently, responsive to reversals of theinstantaneous polarity of the current in the track rails. 7

Located adjacent the ends of the stretch are two end signals S and S forgoverning traffic through the stretch in opposite directions. Each ofthese signals is adapted to indicate stop, caution and proceed, and isprovided with a caution circuit and a proceed circuit as hereinafterexplained.

Located on opposite sides of the middle of the stretch are twointermediate signals and O to transformer T energized.

through wires 47, O and 41 to transformer T.

res ondin to signal S.

' ner :by a relay F "through wire S and S which are controlled in thefollowing manner:

Signal S is controlled by a relay F which in turn is controlled bycontact 5 of relay R The circuit for relay F is from transformer Tthrough wire 37, contact 5, wire 38, relay F and wires Relay F istherefore energized whenever relay R is energized in either normal anddeenergized whenever relay R is de The caution indication circuit forsignal S is from transformer T 42 and 43, contact 44-of re- Ft, wire 45,wire 45, signal S wires 46,

The proceed indication circuit for this signal is the sameas thecautionrcircuit up to and including wire 45, and it then passes throughire'SO, contact Kopcrated by the signal to the right of siding Dcorresponding to signal S, wire .81, mechanismof signal S and wires 46,47, O and 4-1 to transformer T9. Contact K is closed when the signal bywhich it is controlled indicates proceed or caution, but open when suchsignal indicates stop. It will be seen, therefore, that whenever trackrelay is deenergized, signal S will be in the stop position, and thatwhen this relay is energized, the signal will indicate caution orproceed according to the position of the signal to the rightcorlay in asimilar manwhich in turn is controlled bycontact 5 of relay B, so thatwhen relay R is deenergized signal S is in the stop position. Thissignal is also controlled by a contact corresponding to contact K onsignal S Signal S is normally controlled by relay F and by track relayR, the control being such that this signal indicates proceed or cautionaccording as relay R is energized in normal or reverse direction. T heproceed indication circuit for this signal is from transformer-T throughwires 42, 48, and 49, back point of contact 50 of a relay H wires 51 and52, contact 53 of relay F wires 54, and 55, contact of relay R, wire 8,signal S, wires 9, O, and 41, to transformer T. This circuit is closedonly when contact 4 of relay R is swung to the left, that is, only whenthis relay is energized in normal direction. The caution circuit is thesame the proc'eedcircuit up to and including contact 4, and it thenpasses lOto signal S and returns through wires 9, O and 41 totransformer T. The caution circuit is therefore closed only when contact4 of relay R is swung to the rightythat is, when this relay is energizedin reverse direction. It will be seen that so far as the apparatus thusfar described is concerned, signal S will be in ignal is controlled orreverse direction,

branch including a contact 48, back point .OfCOllbfdCt 587 f that thiscircuit is closed only 62, back point the stretch.

relay F The circuit for signal S is provided with i a branch aroundcontact 53 of which branch passes from wire 51, through contact 56 of anauxiliary relay H and wire 57 to wire 55. It follows, therefore, thatwhen relay H is energized, signal S may indicatecaution even thoughrelay R and, consequently, relay F are deenergized. it cannotindicateproceed under these conditions for reasons which will appearinafter.

llhe circuit for signal S is provided with a similar branch relay F"which controls this circuit, this 68 of an auxiliary relay 11*. itfollows then that when relay H ='s energized, signal S may indicatecaution even though relay R, and, conrelay F sequently, relay F aredeenergized.

Auxiliary .relay H is provided with a pick-up circuit which is closedonlycwhen relay 1 is deenergized, this circuit being from --transformerT through wires 42 and relay F, wire 59,-front polnt of contact'6O ofrelay F wire 61, relay H were 62, back point ofcontact 63 of relay lit,and wires 64 and 41 to transformer T". It will be'seen, therefore,

while relays F and H are denergized. Relay is provided with a holdingcircuit which maintains this relay in the energized condition as long asrelay cuit being from transformer T wires 42, 43 and 65, front point ofcontact 66 of relay H wire 67, back point of contact 60 of relay F wire61, relay H wire of contact 41 to transformer T.

It follows fromthe foregoing that when a train moving toward the rightenters the stretch A-B, the consequent opening of relay F closes thepick-up circuit for relay H and "that this relay remains energizedthrough wires 64 and during the passage of the train through the entirestretch, because its holding circuit is closed when relay F while thetrain is in theright-hand end of Consequently, after such train haspassed the middle of the stretch and relay R has become energized,signal S may move to the caution position, eventhough which normallycontrols this signal, is open.

The auxiliary relay H is provided with similar circuits whereby thisrelay becomes energized when a train moving toward the here- F isdeenergized, this cir 63 of relay H and i around the contact 68 of 7 isdenergized, that is, i

' o n l left enters the stretch A-B, and continues to be energized aslong as the train occupies any part of the stretch.

The polarity of the track circuit is controlled by two pole-changers Qand Q operated by the two intermediate signals S and S respectively.These pole-changers are connected in series and serve tocontrol thepolarity of the current supplied to transformer T from a transformer TWhen both of the intermediate signals indicate caution or proceed,current of normal p0- larity is supplied to the track circuit, the C11-cuit for the primary of transformer T then being from the right-handterminal of the secondary of transformer T through wire TO, pole-changerQ wire 71, Q wire 72, primary of transformer T wire 73, pole-changer Qwires 74, G and 47, polechanger Q and wire 75 to the lefthand terminalof transformer T Assuming that the instantaneous polarity of theright-hand terminal of the secondary of transformer T is positive, asindicated by the si n on the drawing, the polarity of the primary oftransformer T at the same instant will be such that the left-handterminal of the primary of this trans former is positive. This is thenormal polarity of the track circuit. It is understood that pole- -ger Qoccupies the position in which is shown when signal S is in eithercauposition, but that this polesed when the signal is in stop positiopole-changer Q is controlled in the same manner by signal S If, then,either signal or 3* moves to the stop position, the correspondingpolechanger will bereversed, so tha e polarity of the track circuit willbe reve d, whereby both track relays l3 and R will "ecome reverselyenergized.

The operation of the system shown in Fig. 1 is as follows:

\Vhen a train moving toward the right enters stretch i i-B, it openstrack relay R, which in turn opens relay F so that signals 53', S and Smove to the stop position. The opening of relay F causes auxiliary relayto become energized. The movement of signal S to the stop position, ofcourse, ses the polarity of the track circuit, but nas no immediateeffect on the signals. tire train approaches the middle of the stretc i,it opens relay R which in turn de r I whereb the holding cir- .ocoinesclosed. The openi 3 also causes signal S to move position. As the trainpasses bethe middle of t is stretch, relay R becomes energized, and thisin turn causes relav F to become energized, so that signal S moves tothe caution or proceed position, depending on the position of the signalto the left corresponding to signal S Signal pole-changer S being in thestop position, current of reverse polarity is' supplied to the trackcircuit, so that relay R is energized in the reverse direction, wherebysignal S moves to the caution position. A following train moving towardthe right can then enter stretch AB with notice that the stretch isalready occupied by another train moving in the same direction. Assumingthat no such second train enters the stretch, however, when the firsttrain passes out of the stretch relay R will become energized, thuscaus-' ing relay F to become energized, whereupon signal S moves to thecaution position and the holding circuit for relay 3 becomes opened.Both signals S and S now being either at caution or proceed, thepolarity of the track becomes'normal, so that relay R becomes energizedin the normal direction, whereby signal S moves to the proceed position.Signal S of course, returns to its proceed position for thesame reason.

eferring now to Fig. 2,'the means here shown for controlling thepolarity of the track circuit comprises two transformers T and T and twocontacts 15 and 17 operated by signals S and S respectively. It is ofcourse understood that the primary wind,- ings of transformers T and T*'are connected with a suitable source of signaling current which is notshown in the drawing. The voltage across the end terminals of thesecondary of transformer T is double the voltage across the secondary oftransformer T and-the secondary of transformer T is provided with amiddleterminal which is connected with a wire 21. For the purpose ofshowing clearly the instantaneous relative polarities, I will assumethat the lefthand end'terininal of transformer T is positive and thatthe left-hand te minal of transformer T is also positive. When bothsignals S and 5 indicate proceed or caution, transformer T is suppliedwith alternating signaling current from transformer T the circuit beingfrom the left-hand end terminal of transformer T through wire 14,contact 15, wire 16, contact 17, wire 18, primary of transformer T andwires 19, O and 21 to the middle point of the secondary of transformer TThe left-hand terminal of the primary of transformer T is then positive,this being the normal instantaneouspolarity of the track circuit. If,now, signal S changes to stop indication, the instantaneous polarity ofthe current supplied to transformer T is reversed, the circuit thenbeing from the right-hand end terminal of the secondary of transformer Tthrough wire 22, contact 15, wire 16, contact 17, wire 18, primary oftransformer T wires 19, O and 21, to the middle point of the secondaryof transformer T The instantaneous polarity of the left-hand terminal ofthe primary of l transformer T then becomes negatlve, so

' circuit is reversed.

signal S changesto-thestop position. Transv a tap at when relay P formerT is then disconnectedfrom transformer T? by contact 17., but thiscontact connects transformer T with transformer T the circuit being fromthe rightehand terminal .of the secondary of transformer T through wire23, contalct- 17, wire 18, primary oftransformer T wires 19, O and13,ito the left-.hand'termina'l of the secondary of transformer T*.. Theleft-hand terminal of the primary of transformer T is then of negativeinstantaneous ipolarity, so that the polarity of the track circuit isreverse.

If desired, the single transformer T with the middle point of thesecondary may beireplaced by two transformers T arranged as shown inFig. 4. Ido not desire to limit :mysel-f, however, to other of thesestructures, as any sui able means may be employed for reversing thepolarity of wire 16 :by circuit controller 15.

Referring :nowto Fig. 8, in the .arrangement :here shown the polarity ofthe track circuit is governed by a pole-changing :relay P, whichconnects the primary of transformer T with the-secondary of transformerA in one/direction or the other, depending onwvhether the relay 1 isenergized or deenergized. In the arrangement here shown, the polarity ofthe track circuit is normal his relay is deenergized. The circuit forthe primaryof transformer T 5, when relay :P is energiizedpisas follows:from secondary of transformer T through wire 25, front point of contact26, wire 27, primary of transformer T wires 28, O 13, and '29, front 1oi11t.of=contact 30, wire 31, to transformer T. The circuit for theprimary of transformer T ,;when relay P is deenergized, will beapparentfrom the drawing. It will, of course, be understood that the primarywinding of transformer T is connected with the source of alternatingsignalingcurrent.

Relay'P iscontrolled by signalsS and S through the medium of contacts 15and 17, the control being such that this relay is energized when bothsignals indicate caution or proceed, but deenergized when either signalindicates stop. Relay P is en rgized from .the secondary of transformerT the primary of which is connected with the source of signalingcurrent. The circuit for relay P is from the secondary of transformer Tthrough wire 32, contact 15, wire 33, contact 17, wire 84., relay P,wires35, 13, O and 36, to the transformerT This circuit is, of course,opened at either contact 15 or 17 I hensignal S or 8* changes to thestop position.

Although I have 'herein' shown-and described only a few forms ofapparatus enr bodying my invention, it is'understood that lay isenergized in normal is 1 energized, and reverse when rssaaar variouschanges :and modifications-may be made therein within the scope of theappended claims withoutdeparting from the spirit and scope of myinvention.

Having thus described my invention, what I claim is: v

1. in combination,

nected with the trackrailsadj acent the mlddle of the stretch, tworelays receiving energy from the track rails .adj acent the ends of thestretch respectively and each responsive to reversals of current, andtwo signals for the stretch one adjacent each end and controlled by saidrelays respectively.

2. In combination, a stretch of railway track a source of currentreversibly connected with the track rails adjacent the mid dle of thestretch, two relays receiving energy from the track rails adjacent theends of the stretch respectively and each responsive to reversals ofcurrent, and a signal controlled by each of said relays.

3. In combination, a stretch track, two :relays receiving energy fromthe track rails adjacent the ends of the stretch respectively and eachresponsive to reversals of current in the rails, two end signals adjacent the ends of the stretch respectively each controlled by theadjacent relay and indicating clear or caution according as the re orreverse direction, two intermediate signals on opposite sides of themiddle trolled by saidintermediate signals for supplying current to thetrack rails adj acent the middle of the stretch in normal direction whenboth intermediate signals indicate proceed or caution and in reversedirection when either intermediate signal indicates stop.

i. In combination, a stretch of railway track, two relays receivingenergy from the track rails adjacent the ends of the stretchrespectively and each responsive to reversals of current in the rails,two end signals adj acent the ends of the stretch respectively eachcontrolled by the adjacent relay eating clear or caution according asthe relay is energized in normal or reverse direcof the stretch and eachcontrolled by the track relay on the far side of the middle of thestretch, and meanscon a stretch of railway.- track, a source of currentreversibly con-' and indii track rails adjacent the ends of the stretchrespectively and each responsive to reversals of current in the rails,means for signaling controlled by said relays, a signal located betweenan end of the stretch and the middle, and means controlled by saidsignal for supplying current to the track rails adjacent the middle ofthe stretch in normal direction when the signal indicates proceed and inreverse direction when the signal indicates stop.

6. In combination, a stretch of railway track, two relays receivingenergy from the track rails adjacent the ends of the stretchrespectively and each responsive to reversals of current in the rails,means for signaling controlled by said relays, two signals located onopposite sides of the middle of said stretch, two pole-changers one foreach signal, each pole-changer being in normal or reverse positionaccording as the corresponding signal indicates proceed or stop, andmeans including said two pole-changers in series for supplying signalingcurrent to the track rails adjacent the middle of the stretch.

'7. In combination, a stretch of railway track, two relays receivingenergy from the track rails adjacent the ends of said stretchrespectively and each responsive to reversals of current, means forsupplying current of normal or reverse polarity to the track railsadjacent the middle of said stretch, and means for signaling controlledby said relays.

In testimony whereof I aflix my signature in presence or" two'witnesses.

HERBERT A. WALLACE.

l/Vitnesses:

A. HERMAN WEGNER, ELIZABETH M. LAIRD.

